Rifle-barrel harmonic vibration tuning device

ABSTRACT

A harmonic vibration tuning device is provided in the forestock of a rifle engaging a cantilevered barrel forward of the rifle action, for the purpose of effecting a change the harmonic vibration frequency of the barrel, that is generated, as a projectile moves through the barrel to the muzzle. This adjustable change in the harmonic vibration frequency of the barrel causing a controllable change in the impact placement of a plurality of fired projectiles. The harmonic vibration tuning device of the preferred embodiment includes a containment assembly that is mounted in a cavity formed in the forestock. The assembly includes a threaded adjustment shaft extending horizontally through the assembly with the shaft being threadedly mated with a reactive contact means. The reactive contact means, of the preferred embodiment, engages the surface of the barrel permitting a force to be exerted between the forestock and the barrel. The threaded shaft protrudes toward the front surface of the forestock to enable it to be rotationally adjusted. The assembly also contains a shaft inadvertent rotation prevention device to apply sufficient force against the threaded shaft to allow both for desired incremental rotational adjustment of the threaded shaft, while at the same time inhibiting undesirable rotation of the shaft during discharge or handling of the rifle. The threaded shaft is secured to the assembly to prevent undesired longitudinal movement of the threaded shaft and the reactive contact means within the assembly. When the threaded shaft is rotated the reactive contact means moves longitudinally along the axis of the barrel. This motion causes a change in the longitudinal contact point of engagement of the reactive contact means and the barrel. This change of longitudinal positioning of the reactive contact means which is engaging the barrel with sufficient pressure, causes a change in the harmonic vibration characteristics of the barrel.

BACKGROUND--FIELD OF INVENTION

This invention relates to control of the accuracy of impact placement ofa projectile fired from a rifle, specifically a device to incrementallyadjust and control the harmonic vibrations of the barrel of a rifleduring discharge in such manner as to allow repetitive accurateplacement of a plurality of fired projectiles.

BACKGROUND--DESCRIPTION OF PRIOR ART

It has been known for years that when a rifle is discharged harmonicvibrations are set up in the barrel of the rifle. It is also known thatthese vibrations of the barrel prior to the projectile leaving themuzzle affect the accuracy of the aimed projectile's impact placement.

Each barrel, no matter how precisely manufactured, has its own uniquevibration characteristics.

The manner in which a rifle barrel vibrates for a given ammunitionloading is dependent upon an number of factors, some of which are: thephysical dimensions of the barrel; whether or not the barrel contactsthe forestock; and also upon the location point and the force of suchcontact, if any, between the barrel and forestock of the rifle.

Many attempts have been made in the past to control or dampen thisvibration. Some of these have been: increasing the diameter and weightof the barrel with the barrel contacting the forestock, as is done intarget rifles; rigidly fastening the barrel to the forestock as is donewith military rifles; and causing the barrel to contact the forestock atsome predetermined point, as is done with most sporting rifles.

Also, because of the uniqueness of each individual rifle's barrelvibration characteristics, no two rifles will have identical accuracywith the same given ammunition loading.

Another way to obtain better accuracy for a given rifle is for therifleman to try out many different ammunition brands and loadings untila load is found that as closely as possible matches the vibrationcharacteristics of the given rifle barrel.

This method, though very time consuming and costly, will usually allowthe rifleman to find a compromise loading that will give moderatelyacceptable accuracy of projectile impact placement.

However, in the aforementioned method of using the selection of anammunition loading in an attempt to match ammunition components to thebarrel's unique vibration characteristics, once an acceptable loading isfound, the rifleman must remain with this single ammunition selection tomaintain this degree of accuracy.

Even if an acceptable ammunition loading is found, if the barrel iscontacting the forestock of the rifle, as is the case with most rifles,should the relationship between the rifle's barrel and stock change dueto such factors as humidity, warpage, or some other cause, thendifferent ammunition components must be found to compensate for suchchanges.

Several patents are directed to providing a specific fixed support pointof contact between the rifle's forestock and barrel, either with orwithout exerting a variable pressure against the barrel, in an attemptto simply dampen the vibration of the barrel.

Exemplary of such devices are shown in U.S. Pat. No. 2,479,594;2,497,861; 2,589,912; 3,060,612; and 4,864,761.

All of the above mentioned Patented devices, by their design, suffer anumber of obvious disadvantages.

One of which is that they all rely on the contact between such deviceand the barrel at a fixed non adjustable location. Another is that theyonly effect a change in the pressure, exerted between the device and thebarrel in an attempt to dampen the barrels' vibration.

However in the operation of these devices, if a change in the adjustmentin pressure to either the undersurface or side surface of the barrel ismade, it also effects a change in the elevation or azimuth of thebarrel's muzzle, which in turn causes an undesirable change in theimpact placement of the fired projectile. Such change then necessitatesthat the rifleman make corresponding adjustments in the sighting deviceon the rifle for each change of pressure against the barrel, which isthe case when using the above mentioned Patented devices.

Also some of the above mentioned Patented devices require that a holeextending through the lower surface of the forestock be made to allowfor their installation. However, if the hole is not drilled in theproper location to allow for the best barrel vibration control, thenanother hole must be made for any subsequent change in their positionwith respect to the longitudinal axis of the barrel. The previously madeholes then would weaken the forestock, or if filled with a substance,would then cause an undesirable appearance in the lower surface of theforestock.

With the advent of better sealant treatments for wood stocks and theincreased use of stocks of man made materials such as fiberglass andother composites, the need for adjusting the change in pressure betweenthe forestock and the side surface or undersurface of the rifle'sbarrel, because of changes in humidity or other environmental factors,to compensate for warpage to the rifle stock, has become much less of aproblem than it was in the past.

Finally although all of the above mentioned Patented devices will dampenthe barrel's vibration, the fact that they all have a barrel contactpoint that is fixed, only allows the devices to have a minimal affect onthe control of the rifle barrel's natural harmonic vibrations.

A simple analogy to help explain why simply applying varying degrees ofpressure at one point on a rifle's barrel has only minimal affect on theharmonic vibrations of the barrel, is this:

If a guitar string is made to vibrate by plucking it, it will emit aparticular tone caused a by specific frequency or harmonic vibrationproduced in the string.

The tone or frequency of this vibration is determined by a number offactors, two of which are: at what point the string is being contactedby the fret of the guitar, and secondly, but less importantly, theamount of pressure being that is being exerted by the finger of themusician on the string against that particular fret on the guitar neck.

As long as sufficient pressure is being applied to the string againstthe fret, a particular harmonic vibration will be obtained. Theapplication of additional pressure to the string, by the finger pressingit against the fret, is of small consequence in producing any furtherchange in the harmonic vibration of the string.

If however the musician moves his finger to a different position on theguitar string and exerts sufficient pressure between the string andanother fret on the guitar, a major change in the harmonic vibrations ofthe string is effected.

In applying the above analogy to a rifle barrel should follow then, thatexerting a variable amount of pressure between a rifle stock and itsbarrel at a fixed position along the barrel, in an attempt to controlthe barrel's harmonic vibrations, will allow only one harmonic frequencyto be affected, and the application of more force between the barrel andforestock than is necessary may only cause additional problems, such asan elevation in the barrel's muzzle.

This above mentioned method of simply applying a fixed position variableforce between the rifle barrel and forestock, is much less effectivethan the method used by the present invention, which exerts instead, asufficient amount of force between the rifle's barrel and its forestockto affect the barrel's harmonic vibration, while permitting the force tobe exerted at adjustably controllable points along the barrel's length.

Each change in the longitudinal point of contact along the barrel causesa different harmonic vibration, therefore allowing this harmonicvibrational change to effect a change in the accuracy of placement of afired projectile's impact.

OBJECTS AND ADVANTAGES

Accordingly some of the objects and advantages of my invention are:

a. To provide a user-adjustable rifle accurizing device that is mountedwithin the forestock of a rifle producing sufficient reactive contactbetween the barrel and the forestock of the rifle to effect a change inthe harmonic vibrations of the barrel upon discharge, with the devicehaving the capability of being incrementally and repeatedly adjusted tochange the point of reactive contact of the device along the axis of thebarrel.

b. To provide the operator of a rifle the ability to incrementallyadjust the harmonic vibrations of a rifle barrel, so that duringdischarge, the adjustment previously having been made, will causeconsistent accurate impact placement of a plurality of firedprojectiles.

c. To provide a way of maintaining stationary positioning of the desiredpoint of reactive contact between the device, the barrel and theforestock, during discharge and handling of the rifle.

d. To provide a rifle accurizing device which when mounted in theforestock is unobtrusive and easy to operate.

e. To allow a rifle's accuracy to remain consistent even when usingnumerous different ammunition loadings, with only a small adjustmentneeding to be made.

Further objects and advantages will become apparent from a considerationof the ensuing description and drawings.

DRAWING FIGURES

FIG. 1 is a graphical representation of a basic form of the presentinvention shown mounted in the forestock of a rifle.

FIG. 2

Is a top view of graphical representation of the basic form of thepresent invention shown mounted in the forestock of a rifle with thebarrel removed.

FIG. 3

Is a graphical representation a cutaway front view of a basic form ofthe of the present invention.

FIG. 4

Is a cutaway side view of the preferred embodiment of the presentinvention.

FIG. 5 Is a cutaway front view showing the reactive contact means andcontainment assembly of the preferred embodiment of the preferredinvention.

FIG. 6

Is a cutaway side view of the rear portion of the containment assemblyof the preferred embodiment, enlarged to enhance display of containedoperational elements.

FIG. 7

is a graphical representation of the preferred embodiment of the presentinvention as it would appear mounted in a rifle forestock.

REFERENCE NUMERALS IN DRAWINGS

1. Forestock

2. Barrel

3. Reactive Contact Means

4. Adjustment Means

5. Containment Assembly

6.Threaded Shaft

7. Securing Tab

8. Force Tensioner

9. Force Tensioner Contact Element

10. Threaded Shaft Anchoring Device

11. Threaded Shaft Adjustment Formed Surface

12. Threaded Bore

13. Threaded Shaft Flat Surface

DESCRIPTION--FIGS. 1-7

FIG. 1

Is a cutaway side view showing the relationship of the Forestock 1, andthe Barrel 2, to a Reactive Contact Means 3, with the Adjustment Means 4being an extension of Reactive Contact Means 3 protruding through theundersurface of the Forestock 1, with a directional arrow indicating thedirection of movement of Reactive Contact Means 3 along the axis ofBarrel 2.

FIG. 2

Is a top view of the Forestock 1 with Barrel 2 being removed, furthershowing the relationship of a Reactive Contact Means 3 to the Forestock1 with a directional arrow indicating the direction of movement of theReactive Contact Means 3 along the axis of Barrel 2.

FIG. 3

Is a cutaway front view further showing the relationship of theForestock 1, and the Barrel 2, to a Reactive Contact Means 3, and itsextension Adjustment Means 4, shown protruding through the undersurfaceof Forestock 1.

FIG. 4

Is a cutaway side view of the present invention showing the ContainmentAssembly 5, the Reactive Contact Means 3, the Threaded Shaft 6, theThreaded Shaft Adjustment Formed Surface 11, the Securing Tab 7, and theThreaded Shaft Anchoring Device 10.

FIG. 5

Is a cutaway front view of the present invention showing ContainmentAssembly 5, Reactive Contact Means 3, with Threaded Shaft 6 beingremoved, to show the Threaded Bore 12 of Reactive Contact Means 3.

FIG. 6

Is a cutaway partial side view of Containment Assembly 5, showing amethod of providing tension against the Threaded Shaft 6, as used in thepreferred embodiment of the present invention comprising a ForceTensioner 8, being a spring, a Force Tensioner Contact Element 9, beinga steel sphere, a Threaded Shaft Anchoring Device 10, for preventinglongitudinal movement of Threaded Shaft 6 and a Threaded Shaft FlatSurface 13.

FIG. 7

Is a cutaway side view of Forestock 1 wherein is mounted ContainmentAssembly 5, containing Reactive Contact Means 3 engaging the surface ofBarrel 2, which is threadedly mated with Threaded Shaft 6, which has aThreaded Shaft Adjustment Formed Surface 11. Securing Tab 7, is shownextending to the lower surface of Forestock 1, whereby a rifle slingattachment can be affixed.

OPERATION FIGS. 1-7

FIG. 1

A adequately sized cavity is formed within Forestock 1 to both receivethe Reactive Contact Means 3 and to allow for sufficient longitudinaltravel along the axis of the Barrel 2, to allow the desired positioningof Reactive Contact Means 3 with respect to Barrel 2.

Reactive Contact Means 3 engages the undersurface of Barrel 2, while atthe same time engaging the lower surface of the cavity formed inForestock 1, causing a force to be exerted between Forestock 1 andBarrel 2.

Adjustment Means 4, is an extension of the Reactive Contact Means 3,which is protruding through a narrow opening in the undersurface ofForestock 1.

If a rifleman wishes to change the point of engagement of the ReactiveContact Means 3, with Barrel 2, he or she applies force against theAdjustment Means 4 to move it forward or backward along the axis of theBarrel 2.

The Reactive Contact Means 3, could be constructed of numerouscomponents and be made of many different types of materials, preferablyhowever, it would be made of a material that would not cause damage tothe surface of Barrel 2.

FIG. 2

Is a top view of a basic form of the present invention with the barrelbeing removed. The operation of Reactive Contact Means 3 is the same asdescribed in FIG. 2.

FIG. 3

Is a cutaway front view of a basic form of the present invention showingthe relationship of Reactive Contact Means 3 to the Forestock 1, and theBarrel 2. The operation of Reactive Contact Means 3 is the same asdescribed in FIG. 2.

FIG. 4

Is a cutaway side view of the Harmonic Tuning Device.

Containment Assembly 5 is of sufficient material and dimension tosupport the operational elements of the present invention. It is arectangular receptacle with an opening in the top having two sidesurfaces and two end surfaces. The two end surfaces each having a nonthreaded hole formed in it to receive the Threaded Shaft 6. It also hasa lower surface having a threaded Securing Tab 7, formed in the exteriorof the lower surface.

Securing Tab 7 which is internally threaded, protrudes downwardlythrough the rifle forestock for the purpose of securing the ContainmentAssembly 5 to the forestock, permitting a sling attachment device to bethreaded into Securing Tab 7 and then tightened to a sufficient force toprevent unwanted movement of the Containment Assembly 5, within theforestock.

Threaded Shaft 6, is threadedly mated with Reactive Contact Means 3.

Threaded Shaft 6 has a formed surface at its end which allows a user toeither grasp the surface or if preferred use a tool such as a screwdriver, Allen type wrench or socket type wrench to rotate Threaded Shaft6.

When Shaft 6 is rotated, Reactive Contact Means 3 travels longitudinallybetween the two ends of the Containment Assembly 5.

FIG. 5

Is a graphical representation of a cutaway front view of the preferredembodiment of the present invention showing the Containment Assembly 5,and the Reactive Contact Means 3 wherein resides Threaded Bore 12 whichthreadedly mates with Threaded Shaft 6. The operation of ReactiveContact Means 3 is the same as described in FIG. 4.

FIG. 6

Is an enlarged cutaway view of one end portion of Containment Assembly 5showing a method of applying force to Threaded Shaft 6 to allowincremental adjustment and positive positioning of Threaded Shaft 6.

Threaded Shaft 6 is anchored in place by Shaft Anchoring Device 10 toprevent it from moving longitudinally within Containment Assembly 5.

Because of the fact, that once an adjustment of Threaded Shaft 6 ismade, it is desirable to have the shaft remain in its last adjustmentposition, Force Tensioner 8 is contained within Containment Assembly 5to effect this desired result.

Threaded Shaft Flat Surface 13 is formed on Threaded Shaft 6 in theproper position to engage Force Tensioner Contact Element 9, which is incontact with Force Tensioner 8 which is compressed when installed intoContainment Assembly 5. One or more of these flat surfaces may be formedon Threaded Shaft 6 to allow for the desired increments of adjustment.

The aforementioned flat surface or surfaces, allow for positiveincremental rotational adjustments of Threaded Shaft 6. The ForceTensioner 8 also supplies sufficient pressure against Threaded Shaft 6to prevent inadvertent rotational movement during rifle handling ordischarge.

FIG. 7

Is a graphical representation of a preferred embodiment of the presentinvention as it might be installed in a rifle forestock.

A cavity of proper dimension is formed within Forestock 1 to receive thepresent invention, with the forward end of Forestock 1 having alongitudinal bore formed therein to accommodate the insertion of anadjustment tool to rotate Threaded Shaft 6.

The undersurface of Containment Assembly 5 rests upon the floor of theaforementioned formed cavity with Securing Tab 7 extending downwardwithin the lower surface of Forestock 1.

When the rifle action is properly affixed to the rifle stock, Barrel 2makes contact with Reactive Contact Means 3.

Because Reactive Contact Means 3 is engaging the floor of ContainmentAssembly 5, which is engaging the floor of the aforementioned cavity ofForestock 1, a force is exerted between the Barrel 2 and Forestock 1.

When Threaded Shaft 6 is rotated it causes Reactive Contact Means 3 totravel in a desired direction along the axis of Barrel 2.

With a force being exerted between the Reactive Contact Means 3 andBarrel 2 this aforementioned change in longitudinal position effects achange in the harmonic vibration characteristics of Barrel 2.

SUMMARY SCOPE AND RAMIFICATIONS

Accordingly, the reader will see that the rifle-barrel harmonicvibration tuning device of this invention precisely controls theaccurate placement of a plurality of fired projectiles from a rifle. Thedevice is easy to operate with the rifle user having only to rotate ashaft to cause a change in the harmonic vibration characteristics of thebarrel thus controlling the projectile's impact placement. Also once adesired adjustment is made it will remain in its adjusted position untilthe user wishes to change it. In addition if a user wishes to changeammunition components he or she can simply change the adjustment of thedevice which will cause a desired change the harmonic vibration of thebarrel to match the ammunition being used, thereby controlling theprojectile's impact placement.

Furthermore the rifle barrel harmonic vibration tuning device has theadditional advantages in that:

it is mounted in the forearm of the rifle stock, therefore being out ofsight, thus causing only a slight change in the outward appearance ofthe rifle.

it has the advantage of being able to be fitted to a newly manufacturedrifle or of being easily installed in a pre-existing rifle

it eliminates the need of the user being limited to one particularammunition loading or brand, in order to obtain consistent firedprojectile accuracy.

it allows precise repetitive repositioning of the reactive contact meansin relation to the axis of the barrel.

it could contain an easily removable reactive contact means that can bereplace if necessary to compensate for wear that may be caused by barrelcontact with it, or for changes in the dimensional relationship betweenthe forestock and the barrel, which may be caused by changes in humidityor other environmental factors.

it allows the elevational point of impact of a fired projectile toremain consistent with the previously fired projectile even afteradjustment.

it allows a repetitive range of adjustment, to allow a minimum groupingof the impact points of a plurality of fired projectiles, without thenecessity of a change in the sighting apparatus of the rifle.

Although the description above contains many specificity's, these shouldnot be construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. For example, the reactive contact means could be ofmagnetic properties, or have a notch in the upper surface that engagesthe barrel, the inadvertent shaft rotation prevention device could be apressure washer, the harmonic vibration tuning device could be affixedto the cavity of the stock by anchoring elements at some point along thethreaded shaft, rather than using a containment assembly, etc.

Thus the scope of the invention should be determined by the appendedclaims and their legal equivalents, rather than by the examples given.

I claim:
 1. In a rifle having a rifle action with a cantilevered barrelfor directing a projectile along the barrel axis and extending forwardlyof the rifle action; said barrel being substantially unconnected withrespect to a stock forearm that extends forwardly beneath the barrel;said stock forearm having an elongated stock body with a lower profilesurface enabling a rifleman to grip and point the rifle and an upperprofile surface having a longitudinal groove formed therein forreceiving the barrel therein without the barrel engaging the entireupper profile surface; a harmonic vibration tuning device mounted in thestock forearm and spaced forwardly of the rifle action; said harmonicvibration tuning device comprising:a reactive force application means incombination with a longitudinal position adjustment means incorporatedin such a manner as to provide for repetitive precise longitudinalpositioning of said reactive force application means to a desiredlocation along the axis of the barrel and the stock forearm, whileexerting a force between the stock forearm and barrel, with said forceeffecting change in harmonic vibrations of the barrel as a projectiletravels through the barrel.
 2. In the rifle according to claim 1 whereinsaid reactive force application means is a reactive contact means.
 3. Inthe rifle according to claim 2 wherein said reactive contact means is ofsufficient dimension to allow physical contact between the surface ofsaid barrel and said stock forearm when said rifle action is affixed tosaid stock body.
 4. In the rifle according to claim 1 wherein saidreactive force application means is a magnet.
 5. In the rifle accordingto claim 2 wherein the harmonic vibration tuning device furthercomprises a containment assembly of sufficient dimensions to providesupport and containment of the reactive contact means and additionaloperational elements of the harmonic vibration tuning device.
 6. In therifle according to claim 5 wherein said additional operational elementscomprise a threaded shaft; a shaft anchoring device; and a shaftinadvertent rotation prevention device.
 7. In the rifle according toclaim 6 wherein said reactive contact means has a threaded longitudinalbore of adequate dimensions formed therein to threadedly mate with saidthreaded shaft.
 8. In the rifle according to claim 2 wherein saidreactive contact means is a nylon block.
 9. In the rifle according toclaim 6 wherein said threaded shaft has an adequately formed surface atone of its ends to allow mating with an adjustment tool, and being ofsufficient length to permit desired motion and longitudinal positioningof said reactive contact means along the axis of said barrel.
 10. In therifle according to claim 6 wherein the shaft anchoring device comprisesan element of sufficient dimension to secure said threaded shaft in sucha manner so as to prevent undesirable longitudinal movement of thethreaded shaft within the containment assembly.
 11. In the rifleaccording to claim 6 wherein said shaft inadvertent rotation preventiondevice inhibits undesirable rotational motion of said threaded shaftduring handling or discharge of the rifle; said shaft inadvertentrotation prevention device comprising a force tensioner element; and aforce tensioner contact element.
 12. In the rifle according to claim 11wherein said force tensioner element is a spring.
 13. In the rifleaccording to claim 12 wherein said force tensioner contact element is asteel sphere.
 14. In the rifle according to claim 13 wherein said springis installed in such a manner so as to exert a force upon said steelsphere.
 15. In the rifle according to claim 13 wherein said threadedshaft has a flat surface formed thereon to engage said steel sphere insuch a manner so as to prevent undesired rotational motion of thethreaded shaft.
 16. In the rifle according to claim 5 wherein saidcontainment assembly has an undersurface with a downwardly extendinginternally threaded securing tab formed thereon, and of sufficientdimensions to threadedly mate with a rifle sling attachment device forpermitting secure attachment of the containment assembly to the stockforearm.